1. Field of the Invention
The present invention relates to improvement of a fuel cell construction.
2. Description of the Related Art
In a fuel cell, an electrically conductive member is interposed between a flow passage forming member and a fuel electrode or between a flow passage forming member and an oxygen electrode, thereby to conductively connect adjacent cells via the flow passage forming member and the conductive member. Also, as fuel gas is caused to flow between the passage forming member and the fuel electrode, i.e. through the conductive member charged within a fuel gas passage, the fuel gas is caused to flow while contacting the fuel electrode. Or, oxygen-containing gas is caused to flow between the passage forming member and the oxygen electrode, i.e. through the conductive member charged within an oxygen-containing gas passage, the oxygen-containing gas is caused to flow while contacting the oxygen electrode.
Conventionally, the conductive member is formed entirely uniform, and such uniform conductive member is charged within the entire space between the passage forming member and the fuel electrode or between the passage forming member and the oxygen electrode. Accordingly, the entire fuel gas flowing through the fuel passage is caused to flow through the conductive member over the entire area of this fuel passage. Or, the entire oxygen-gas containing gas flowing through the oxygen-containing gas passage is caused to flow through the conductive member over the entire area of this passage.
However, although the conductive member is provided with a porous construction in order to allow passage of gas therethrough, the conductive member provides significant resistance against the gas flow. Thus, it has been necessary to increase the feeding pressure of the fuel gas or oxygen-containing gas to be circulated through the conductive member.
Therefore, a gas passage provided in communication with the fuel gas passage for allowing supply of the fuel gas to this fuel gas passage or a gas passage provided in communication with the oxygen-containing gas passage for allowing supply of the oxygen-containing gas to this oxygen-containing gas passage needs to be maintained under gas-tight condition against such high gas feeding pressure. For this purpose, members for constituting the gas passage need to be formed of material having high pressure resistance, or a high-performance sealing construction was needed to maintain the gas passage under the gas-tight condition. And, these requirements have led to increase of the costs of the fuel cell.
The present invention attends to the above-described state of the art, and a primary object of the invention is to make it possible to reduce the feeding pressure of the fuel gas or oxygen-containing gas to be fed through the conductive member so as to achieve cost reduction of the fuel cell.